1. Field of the Invention
The present invention relates to a method of sorting copy sheets and a sorter (automatic page arrangement device) which is capable of automatically classifying and arranging copied sheets when a plurality of sheets are copied from an original document, and, particularly, to a sorter for use in a copying machine which is intended to increase the number of copy sheets which can be accommodated in trays that are vertically arranged in multiple stages at predetermined intervals.
2. Description of the Prior Art
FIGS. 1A and 1B illustrate a conventional sorter which is used in a copying machine for automatically classifying and arranging a plurality of copy sheets. The copying machine-sorter arrangement of FIGS. 1A and 1B comprises a document feeding device 1 for automatically feeding an original document; a platen 2 for receiving the original document which is fed from the document feeding device in a predetermined position; an optical system 3 for projecting a picture image of the document which has been placed on the platen 2 onto an exposing station B; a photo-sensitive drum 4 which is capable of turning along its circumference past a charging station A, the above-mentioned exposing station B, a developing station C, a transferring station D and a cleaning station E (including an electrical discharger); a copy paper feeder 5; a fixing station F for fixing the picture image which has been transferred onto a sheet of copy paper; a discharge belt 6 for discharging a copied sheet into a sorter 20 with the help of discharge rollers 7; an actuating panel 8 for issuing commands for various operations; and the sorter 20 which is provided at the side of a copying machine 10. The sorter 20 comprises a first endless belt 21 for conveying a copy sheet which has been discharged through the discharge rollers 7; a second endless belt 23 for conveying a copy sheet to an indexer 22 in cooperation with the first endless belt 21; and the above-mentioned indexer 22 for classifying and delivering copy sheets to the respective multi-stage trays 24.
The operation of the conventional copying machiner-sorter arrangement will now be described. Each of the copy sheets which has been successively discharged from the copying machine 10 is deflected by the second endless belt 23 and guided by the indexer 22 so that it is introduced into the respective trays 24, one after another, successively, from the upper tray to the lower trays.
However, in this sorter 20, each of the sorted copy sheets 25, which is deflected by the second endless belt 23, guided by the indexer 22 and then received in the tray 24, is curved downward, as shown in FIG. 1C, because the sheet is supplied with uneven stress in the direction of its thickness when it is deflected. If the respective copy sheets received in the trays 24 are curved downward, the front end of a further copy sheet which next enters any one of the trays 24 will hit upon the end 25a of a previously sorted copy sheet 25 since the end 25a projects upward beyond the height of the tray 24. Accordingly, paper jams occur in the indexer 22. Even if no paper jams occur, because the end 25a projects upward, it is apparent that the copy sheet capacity of the trays 24 is reduced.